Abstract
In contrast to S. typhimurium [19], S. enteritidis is a serotype which has its primary food-animal reservoir in poultry. To date, phage typing has been of paramount importance in studying the epidemiology of this serotype and in particular, has demonstrated the involvement of both poultry meat and whole shell eggs in the transmission of S. enteritidis PT4 to humans. The findings discussed above describe various aspects of the serotype, particularly in relation to the involvement of both LPS and plasmids in its virulence and phage type identity (Fig. 2). These findings have led to an increased understanding of the biology of this serotype, which is of major importance in human food-poisoning in England and Wales at the present time.